RadioRon
Well-Known Member
Hrrm, here's a question then. If cell phones are licensed on their power output through a resistor load could I hook a micro yagi or biquad to my cell phone and still be legal?
Man, you had to ask a question that takes some serious time to answer! First off, understand that there is two aspects to this. One is the equipment authorization, which applies to the individual cellphone and certifies that the phone meets certain technical requirements. Then there is the license, which is different but the licensee cannot use anything but authorized equipment. The license is granted to the cellphone company on whose system your phone operates, so they have a responsibility to FCC to maintain their system within technical limits, and this includes "their" phones.
Here is an example. Nokia FCC ID EO25ZVPC105A.
The grant of equipment authorization states that the device is regulated by Part 22 of the FCC rules, and has an output power maximum of 0.6 watts (conducted). So, then when you look up part 22 it says that mobile transmitters must not exceed an ERP of 7watts. (part 22 covers cellular channels below 1 GHz, while part 24 covers PCS which is 1850Mhz and thereabouts). This implies that you would not be illegal if you put an antenna with gain of up to10.6 dB on this device. But wait.
PCS devices under Part 24 must not exceed 2 watts EIRP peak power (ref CFR47.P24, 24.232). If you were dealing with a CDMA mobile phone in this band, then the conducted authorization would again be 0.6 watts, but now you could only add a 5.2 dB gain antenna. Slightly lower for a GSM phone. But wait.
Now, having said all that, remember that it is the cell company (Verizon or whoever) that holds the license for your phone, and I am going to guess that you need their authorization to change anything in one of their phones, in order to be strictly "legal". I would also guess that they might say no if you asked their permission because when you increase tx power, you mess up their cellular coverage structure, depending on where you are and where you point your antenna.
Now, there is also the issue of the fact that the phone is also certified as a part 15 device when it is not transmitting. This certification probably also does not allow you to change the antenna.
Then there is the other rules that apply to personal communication devices, those that deal with radiation hazards. These dictate how much power you can feed into your antenna, at a maximum, depending on the distance between the antenna and any people.
So, I'm afraid it is a bit more complicated than we all would like it to be. From the cellphone system operator's point of view, adding an external antenna might mess them up, so they probably wouldn't like it unless their engineers gave the go-ahead.
Whew, that was a lot of typing. Can we change the subject now?